Microelectronic devices generate heat as a result of the electrical activity of the internal circuitry. In order to minimize the damaging effects of this heat, thermal management systems have been developed to remove the heat. Such thermal management systems have included heat sinks, heat spreaders, fans, and various combinations that are adapted to thermally couple with the microelectronic device.
With the development of faster, more powerful, and more densely packed microelectronic devices such as processors, traditional methods of cooling may be ineffective, inefficient, or impractical. For example, processors may have local high heat flux regions called hot spots that create elevated and non-uniform temperature distributions within the die package and cooling system. Resultant overheating compromises the reliability and speed of such devices. Hot spots may need more cooling than traditional cooling methods can provide. In this regard, improved cooling technology is needed to remove the generated heat from localized hot spots of microelectronic devices to prevent overheating.
Thermoelectric coolers (TEC) or Peltier devices and associated techniques are emerging as an improved thermal solution for high-power, densely populated microelectronic devices such as processors and other integrated circuit dies. A thermoelectric cooler may have a cold side where heat is absorbed by electrons as they pass from a low energy level in a p-type semiconductor element, to a higher energy level in an n-type semiconductor element. A power supply may provide the energy to move the electrons through the system. At a hot side, energy may be expelled to a heat sink as electrons move from a high energy level element (n-type) to a lower energy level element (p-type).
One current technique employs a TEC directly deposited on the back side of a die (U.S. Pat. No. 6,365,821). Placement of the TEC on the die, however, presents several problems. First, placement on the die creates power delivery problems; providing power to the TEC through the die is difficult because the back side of the die is typically inactive. Also, creating a power supply to the backside of a die involves tampering with an expensive and sensitive die fabrication process. Second, the creation of TEC elements on the backside of a die complicates die fabrication by introducing one or more additional step(s) and material set(s) into the fabrication process. Finally, placement of the TEC on the die backside may not remove heat as effectively as a TEC placed elsewhere. Therefore, improvements are needed to enhance TEC cooling efficiency of local hot spots, to more simply provide power to a TEC, and to provide spot cooling benefits of a TEC without unduly complicating the die fabrication process.